CA2799034A1

CA2799034A1 - Multi-physics fuel atomizer and methods

Info

Publication number: CA2799034A1
Application number: CA2799034A
Authority: CA
Inventors: John Amaya; Luke Cruff; Joseph Lull; Marcel Prado; Bradley J. Vieau
Original assignee: Lytesyde LLC
Current assignee: Lytesyde LLC
Priority date: 2010-05-20
Filing date: 2011-05-09
Publication date: 2011-11-24
Anticipated expiration: 2031-05-09
Also published as: US20210215124A1; US20140191055A1; US20170370331A1; PT3650125T; DK3650125T3; PL2571624T3; US20110284652A1; EP2571624B1; CN102905795A; PT2571624T; IL223114A; RU2569797C2; JP2013532247A; AU2011256471A1; US20190107085A1; EP3967868A1; RU2012155203A; IL223114A0; US11674479B2; US20160245241A1

Abstract

A fuel atomizer that includes a housing having a fuel inlet and at least one primary orifice positioned at the inlet, wherein the at least one orifice configured to disperse a stream of fuel into a plurality of fuel droplets. The plurality of fuel droplets contact a fuel impingement surface to break up the plurality of fuel droplets into a plurality of smaller secondary droplets and create a thin film of secondary droplets on the impingement surface. At least one pressurized air channel delivers an airflow into contact with the secondary droplets. The secondary droplets pass through a plurality of secondary outlet orifices to exit the housing. A size of the plurality of secondary droplets is reduced when passing out of the plurality of secondary orifices.

Description

MULTI-PHYSICS FUEL ATOMIZERAND METHODS

TECHNICAL: FIELD

100011 The present. disclosure. is directed to fuel aysteiiis;_ and more particularly directed to, fuel delivery systems that. use multiple stages to .enhance evaporation. of the:fuel.

BACKGROUND
100021 Many types of-devices have been.:developed over the: years for the purpose of converting Liquids :into aerosols' or.frie particles readily converted into. a gas-phase. Many such;devices have been developed, for example, to, prepare fuel tfor use.. in internal combustion engines.. To optimize fuel, oxidation within an engine's.
combustion chamber, the fuel must be. vaporized,, homogenized with air, and in a chemically-stoichiometric gas-phase mixture. Ideal fuel atomization and, vaporization enables `more complete, combustion and consequent, lower engine out..
pollution.

[0003] More, specifically, relative to internal ..combustion engines, stoichiometricity is a condition where the amount of oxygen ,required to completely' burn a given amount of fuel is supplied in a homogeneous mixture resulting in optimally correct combustion with. no residues remaining from. incomplete or inefficient ;oxidation. Ideally,: the. fuel should be completely vaporized, intermixed with air,, and homogenized prior to ignition for proper oxidation.. Non-vaporized fuel droplets do not ignite or combust completely in conventional internal and external combustion engines; which -degrades fuel efficiency ;and. increases engine out pollution.

100041 Attempts to reduce or control. emission byproducts. by adjust' temperature and pressure typically affects the NO byproduct: To,meet emission standards, these residues must be.dealt-with, typically requiring after -:
treatment?:in a.
catalytic converter, or a- scrubber. Such treatment of these residues results' 'in additional fuel costs to operatc..the catalytic converter or scrubber and may require additional component -costs as well as packaging and mass in pl"ications.
Accordingly,. any reduction in engine out residuals resulting from incomplete combustion. would be economically and.envi'ronmental,ly'beneficial.

[0005J Aside from the problems discussed above, a: fuel that is not completely vaporized in a chemically stoichiometric: air/fuel mixture :causes the combustion.engine:..to perform at less than: peak .efficiency..A smaller portion of the:
fuel.'s., chemical energy is converted to mechanical energy when fuel is. not completely combusted. Fuel energy is wasted and..,unnecessary 'pollution is.
created.
Thus, by- further breaking down and more completely vaporizing, the fuel-air:
mixture, better fuel cfficiency_inay be available.

[0006]. Many' attempts 'save been made to. alleviate the above-described problems with respect to fuel. vaporization and incomplete fuel, combustion.
In.
automobile: engines,. for example, 'inlet port or direct fuel injection have,:
almost.
universally replaced "ca"rburetion for fuel delivery.. Fuel injectors spray fuel directly into the inlet port or cylinder. of* the engineg and. are controlled electronically:
Injectors facilitate more precise metering and control of the amount of fuel.
delivered

2 to each cylinder independently relative. to carburetion.. This reduces or eliminates charge transport time facilitating optimal transient operation. Nevertheless, the fuel droplet size of.a fuel injector spray is not. optimal and there is. little time for the .fuel to mix with air prior to ignition.

[0.007] Moreover, it has been recently discovered that fuel injector sprays are accompanied by a~ shoek.wave in. the fuel spray. The shockwave.'may prevent the fuel from fully mixing with air. The-shockwave appears to. limit fuel mass to certain areas of the piston, limiting the fuel droplets' access to.air.

[00081 Other prior systems, such ;as heated injectors and. heated, fuel rails have also been developed in attempts to remedy the problems related to fuel vaporization and incomplete fuel. combustion.

DISCLOSURE- OF THE INVENTION

100091 The :principles described herein may address some of the above-described deficiencies and others. Specifically, some of the principles described.
herein relate to liquid processor apparatuses and methods.

[001.0] One aspect provides a. fuel atomizer that-includes a housing having.
a fuel inlet, at least one primary fuel exit orifice, a fuel impingement surface,. at least one air, or oxidant,, inlet :or supply channel, and a plurality of secondary atomizer outlet orifices. At least one ;primary orifice is positioned at the fuel inlet and, is configured to disperse a stream of fuel into a plurality of fuel droplets.
The, fuel impingement surface is configured and arranged to be contacted by the plurality of fuel droplets to break up the plurality of fuel droplet into a plurality of smaller

3

4 PCT/US2011/035758 secondary droplets and create a thin film of secondary fuel droplets on the impingement surface. At, least one pressurized. air channel is configured to deliver an air flow into contact' with the secondary droplets. The. plurality of secondary orifices.are arranged to have the secondary droplets pass througl 'to exit the housing.
The size of the plurality of .secondary droplets is reduced when passing through ::the plurality of secondary^ orifices.

[00.111 At least one primary orifice positioned at. the fuel inlet may be .arranged coaxially with the fuel, impingement surface. 'The. plurality of secondary, droplets may accelerate to< high, velocity speed when passing.. through tlie plurality of secondary orifices,. The, housing may be one of a manifold, a cylinder, a head cornbustion_chamber, and an intake port into a cylinder head. The fuel impingement surface may. be arranged at', an angle in. the range of about, but not constrained or limited to 90 degrees to about .115 degrees relative: to a longitudinal axis of the housing: The plurality of secondary orifices, may be arranged 'at an angle.
between about 0 degrees-and about. 90 degrees relative to a longitudinal axis of the housing.
The fuel atomizer may further comprise a. fuel metering member that defines the primary fuel inlet orifice.

[0012] Another aspect 'of the present disclosure. :relates to a method of atomizing fuel that includes providing an atomizing device comprising at least, one primary orifice, an impingement surface, a mixing' -chamber; and a plurality of secondary orifices, passing a stream of'fuel' through the at least one primary orifice, to create a plurality of first. fuel droplets, and contacting the.plurality of first fuel droplets against the impingement surface to break up the plurality of fuel droplets into a plurality of smaller sized secondary droplets and create a thin film of secondary. droplets on' the impingement surface. The method also includes mixing the plurality of second droplets with a pressurized air flow to form, a fuel/air, mixture, :passing, the fuel/air mixture through the plurality of secondary orifices to shear the plurality of second droplets into a. plurality of smaller sized third droplets, and dispersing the plurality of third droplets from the. atomizing device.

[00131 The =step of providing the atomizing device may include arranging at least one primary fuel orifice, the impingement surface, and plurality of secondary orifices coaxially. Mixing the plurality of second droplets with a .pressurized air flow may include delivering a flow of air in a direction. that is at least partially radial. Passing the fuel/air mixture through the. plurality of secondary orifices: may include rapid acceleration of the fuel/air mixture to high. velocity speeds'.
The atomizing device may further. include a fuel metering device that, defines at least one primary orifice, and passing a stream of fuel through the at least one primary orifice with the, fuel metering. device.

[00141 A further aspect of, the present disclosure relates to a pre-combustion fuel mixing device that includes a housing, .:a valve, a first nozzle member, an impingement surface, a mixing. chamber, a plurality of air passages, a plurality of second, orifices, and a dispersing nozzle. The :valve is:
enclosed by the housing and arranged to deliver a stream of fuel. The first nozzle member includes a plurality of first orifices, wherein passage of the stream. of fuel through the plurality of first orifices creates a plurality of first fuel droplets. The impingement surface-is arranged in a flow path of the plurality of first fuel droplets, wherein contacting the plurality of first fuel droplets against the impingement -surface breaks up the plurality of first fuel droplets into a .plurality of smaller sized second droplets. The plurality of angled air .passages leads into the mixing chamber,., wherein a flow of pressurized air is delivered through the. air passages to..mix with the plurality of second droplets to create a fuel/air mixture. The plurality of second orifices :are arranged. to have the fuel air, mixture pass, wherein the plurality of second droplets:
accelerate to high velocity (e . g sonic) speed when passing: through the plurality of second` orifices: to :reduce a size of the plurality of second droplets to a.
plurality of smaller sized third droplets. ' the dispersing nozzle spaces .apart the plurality of third droplets to permit an increased evaporation rate,of the plurality of third droplets.

[001S1 At least"a portion of the impingement surface may be arranged at an angle relative to a, longitudinal axis of the device. The. dispersing nozzle:
may be.
removably mounted to the housing, or fully integrated as 'a single :component.
The plurality.of,angled air passages may be arranged at an angle relative to a longitudinal axis of the device. The plurality of angled air passages may include a secondary angle relative to the impingement .surface, thereby forming. a. compound angle that induces a helical rotation. to.. the pressurized air flow. The plurality of secondary orifices may be arranged at an angle relative, to a longitudinal axis of the.
device.

(0016] Another aspect of the present disclosure relates to a method of' vaporizing: fuel that includes providing a fuel :atomizing device that includes a fuel metering device; an impingement surface, and a plurality of outlet orifices;
controlling a pressurized air flow to deliver air through the:-housing and out of the plurality of outlet orifices to create an air flow, and controlling a fuel supply to deliver a flow of fuel from the. fuel metering device onto the impingement surface, the flow of fuel including a plurality :of first fuel droplets that break up into smaller sized second, fuel droplets --.upon contacting the: impingement surface. The method .also includes mixing the second fuel droplets with the air flow,.moving thesecond fuel droplets through the plurality of outlet orifices, the second fuel droplets breaking up intosmaller sized third. fuel droplets upon exiting. the plurality of outlet orifices,. enhancing, accelerating or promoting rapid -vaporization of the third fuel droplets as the third fuel droplets disperse from the plurality of outlet orifices. The, method:,-may further include. controlling the fuel source. to turn OFF the flow of fuel while :maintaining the. air flow. and controlling the pressurized air source to: turn.
OFF the'air flow:

BRIEF DESCRIPTION:~OF THE.D.RAW.INGS

100171 The accompanying drawings illustrate, certain embodiments, discussed below and. area part. of the specification.

1001-8] FIG, I is a perspective view of an example fuel system iii., accordance with..the-present disclosure.

[00119] FI:G.;2 Is an exploded. perspective view, of the fuel system of FIG.
1.
100201 FIG. 3 isa sidc'vie.w of the fuel system of. FIG. 1.

[0021] FIG. 4 is ;a top view of the fuel "system of FIG. 1.
[0.022] FIG. 5 is a front view of the fuel. system of FIG. 1.

[0023] FIG. 6 is a cross-sectional side view of the. fuel system of. FIG. 4 taken along cross-section indicators 4-4.

[0024] FIG. 7 is a cross-sectional top view of the fuel system of FIG. 3 taken along cross-section indicators 3-3.

10025] FIG. 8 is -a detailed view of a portion-of the fuel system.of FIG:'7.
100261 FIG. 9 is a top view of another example- fuel system. in; accordance with the present -disclosure..

[0.0271 FIG. 10 is-a `cross-sectional ,side view. of the fuel system of FIG. 9 taken: along cross-section indicators 10-101.

(0028-] FIG. 1.1 is :a detailed view of a portion of the fuel system shown in.
FIG. 10..

[00291 FIG, 12 .is, a side view of another example fuel, system in accordance with the present. disclosure.

[0030] FIG. '13 'is.a bottom view of the fuel'.system of FIG. 13.

[003.1( FIG..14 is a. cross-sectional side view of the fuel system of FIG. 12:
taken along cross-section indicators 14-14.

[.00321 FIG. 15 is. ;a detailed view of a portion of the. fuel system of FIG. 14.

[0033] FIG. 1'6 is a side view of an atomizer, of the fuel system of FIG. 1.
[0034] FIG. 17 is a rear view-ofthe.atomizer;of..FIG.- 16:

[0035] FIG.. 18 is a front view of the atomizer of FIG. 16.

10.036] FIG. 19 is a cross-sectional view of the atomizer 'of FIG. 16 taken along cross-section indicators 19-19.

[0037] FIG'.'20 is a cross-sectional view of the atomizer -of FIG. 19'taken along cross-section indicators 20-20.

[0038] FIG. 21 demonstrates a pressurization stage of operation of the fuel system of FIG. 1.

100391 FIG. 22 demonstrates further development of' the pressurization stage-of FIG. 21.

10040:1 FIG. 23 demonstrates a first orifice break up stage of operation of the fuel system of FIG, 1.

"10041.] FIG. 24 demonstrates an impingement break up stage of operation of the fuel system of FIG. 1.

X00421 FIG. 25 demonstrates a thin film break up. stage of operation of.the fuel system" of FI.G. 1.

100431 FIG..26 demonstrates a sonic velocity break up stage of operation of the fuel system of -FIG. 1.

[00441 FIG.-'27 demonstrates "a fuel purge stage of operation of the fuel system of FIG. 1..

[00451 FIG." 28 demonstrates an air evacuation stage of operation of, the fuel system of FIG. 1.

[00461 FIG. 29 illustrates an idle stage of operation of the fuel system of FIG. 1.

[0047] FIG.. 30 is a.graph showing an example air and fuel sequencing of a fuel. system according to the present disclosure.

100481 Throughout the drawings, identical reference characters and descriptions indicate similar,. but not necessarily identical elements.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

(0049) Illustrative embodiments and aspects .are described below. It will,, of course,. be appreciated. that in the development of any such actual embodiment, numerous. implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with :system-related and business-related constraints, that will. vary from one implementation to another.
Moreover,, it will be appreciated that such a development effort -might 'be complex and `time consuming, but -would nevertheless be a routine undertaking for those of ordinary Will in the art having the benefit of this disclosure.

100501 As:used throughout the specification and. claims, the term."droplet"
refers to a small sized drop of liquid. The,drop. of liquid may have any shape and volume. A droplet may include a single drop of the liquid or multiple drops.
of the liquid combined together, possibly. in a serial-arrangement. The words "including"
and '-having,": as used in the specification, 'including' the, claims, have.
the, same meaning as the:word "comprising."

(0051] The,present 'disclosure is directed to fuel preparation systems and methods. However,, small particle technology-has benefits in.many applieations.such as,high altitude or,low orbit applications and underwater applications. One.
aspect of the present disclosure relates to the use of multiple physics phenomena to-change"a liquid: state fuel into a fine partic-le mixture readily convertible into a.
gaseous state.
The, change from liquid to gas may occur in a plurality of steps that. each utilize a different physics phenomena. For example, a first step.mayinclude breaking down a continuous stream of liquid fuel into a plurality of first droplets or strings of connected first droplets by passing the stream of fuel through a single orifice or multiple orifices using liquid energy. In this step, a fluid stream under pressure may be forced through small orifices of, for example, a coritrolled metering device, to create initial formation of the, first droplets-. Single or multiple.metered streams may be employed to enhance the. initial formation of the first droplets and direct the.
droplets toward 'the next stage.

[00521 In. :a second step, the first droplets: are broken up through mechanical impingement utilizing liquid energy. In this second step, the first.
droplets or strings of first. droplets are impacted against an obstacle such as an impingement surface. This impact .results in break, up. of the first droplets into smaller sized second droplets due, to rapid, deceleration and considerable droplet deformation. The impingement surface is typically positioned within an optimized distance from the.metering device to facilitate the break up of first droplets into smaller second droplets.

[00531 In a third step, the film, or droplets leaving the impingement feature, experience a high shear as they enter the. surrounding' air flow. The shear causes further distortion of the droplets .and further break up.

[00541 In a fourth step the third droplets are' sheared by passing through multiple orifices utilizing gas energy. The third droplets are introduced into, an air-flow within a mixing chamber to forma two-phase mixture of air ;and fuel droplets.
The two-.phase mixture is forced through a secondary plurality of orifices where the third droplets are rapidly accelerated to high velocity (e.g., sonic) speed.
The rapid acceleration shears and breaks up the third droplets into smaller sized fourth droplets. Sonic. speed is typically in. the range of about 768 mph at. room.
temperature or about 330 m/s at 20 C.

100551 The system typically utilizes up to sonic gas: velocities to cause.
droplet breakup. Sonic velocity (or sonic: speed) is a function of the fluid properties and conditions. For air at standard. sea-level temperature, pressure and humidity conditions, the sonic velocity ;is. about 341, m/s. For compressed air at 4bar; 350K
the sonic velocity is typically abut 375 m/s: The. system may -operateusing a range of fluids, temperatures and pressures causing a change in the sonic..
velocity..
However, the ratio of'the-actual velocity achieved to the. sonic velocity (known as>
the Mach number) should retrain relatively constant; and may be up to 1Ø

(00561 In, fifth step, the fourth droplets are dispersed in. a spray pattern in which the fourth: droplets are- separated from each other.. The increased separation between fourth =: droplets facilitates faster vaporization due to locally.
steeper vapor concentration gradients wherein there is less interference between vapor clouds of adjacent droplets. A pressure differential present as the, fourth droplets are dispensed from the system may also tend to increase 'vaporization rates of the 'fourth droplets.

100571 Turning now to the figures. ,and in particular to FIGS. 1-8 and. 16-20, one embodiment of a fuel system "1:0' is shown. The fuel system 10 may comprise, for example, a base 12,, a fuel 'metering device 14, and an atomizer 16.
The fuel system 10 may provide a premixed supply of fuel.-and oxidant to a device such as, for example, an internal combustion engine. FIG. I illustrates the fuel system 10 in a manifold application wherein the base .12 defines at least in part a manifold for use in a.combustion: engine., [0058) The. base 12 is a generally rigid structure that may be made of metal, ceramic, composite, plastic, or.other materials. The base: 12 may enclose a number of internal components. The base 12:may include a number. of cavities or seat features within. which. various components are mounted. For example, the'-base 12 may include ai, atomizer. cavity 20 within which at least a portion of the' fuel metering, device 14. and atomizer. 1.6 are mounted. The base 12 may also-include a dispense cavity '22 wherein the atomizer '16 dispenses a two-phase air/fuel.
spray.
The base 12 may also. include an air intake assembly: 24 that., provides a.supply. of air to the atomizer 1.6. The base 12 may comprise any size or. shape. The base 12 may be configured in other embodiments in the form:of, for example, abase portion of an intake :port 1.12 (see .FIGS. 9-11) .or a base portion of cylinder head 212 (see FIGS.
1245) as described in more,.detail below:

10059) Referring to'.FIGS. 2 and .S,- the fuel,:metering device 14 includes _,a valve :assembly 30 and =an outlet 32 positioned at a. distal end. 34. A fuel metering device 14 may be configured to.provide controlled fuel flow to theatornizer 16.. The fuel metering,:device l 4 may include at least one orifice that provides break up of,'a stream of fuel into a plurality of droplets or :strings of droplets of 'fuel'.
In some examples, the fuel-:metering device 14 includes-'a plurality of orifices.,.
A.supply of fuel is delivered from the fuel metering device. under pressure and forced through a relatively small orifice or orifices for initial formation of droplets.
Multiple metered streams of droplets may be created as fuel exits the: outlet of the fuel metering device 14. The streams of droplets may be directed toward another portion of the-atomizer such as an impingement-surface-as described in further detail below;

[.0060] In some embodiments, features. of the fuel: metering device 14. may be. included, with the atomizer .1.6_. For. example, one or more orifices used 4o create, droplets from the supply of firel controlled by the fuel metering device 14 may be integrated into the atomizer 1..6c In other,arrangements, `features of `the atomizer 1.6`
may be integrated -into the fuel, metering device 14.. In, some, examples;. -the fuel metering device 14 and atomizer 16 may be' integrally formed or assembled as a single device.

[00611 The fuel metering device 14 may be an off-the-shelf fuel metering device, fuel injector, or other readily available fuel me.teringlor control device. In at least: one example, the fuel metering device 14 may be any :device that provides a controlled flow of fuel :to the atomizer 16. and :directs that flow of fuel onto a.surface of the atomizer such :as an impingement surface. In one example, the fuel metering device 14 may be a bore. hole injector' that provides a single stream.. of droplets or strings of droplets.of'fuel. In other examples, the,. fuel metering device 14 :provides two, or more stream of droplets, a partially broken. stream of fuel, or a, continuous stream of fuel.

[00621 Referring now to FIGS. 2,_ 8 and 16-20, the atomizer 16 includes :a housing 40, a fuel metering device cavity 42, and a fuel inlet 44. The housing 40 is mounted within the atomizer cavity 20 of the base 12. The housing 40 defines the fuel metering device cavity. 42, which cavity is, sized to receive at least a portion of the fuel metering device 14. First and. second pressurized air sealing members 56, 58 may be positioned between the housing 40 and the atomizer cavity 20. A
third sealing member 60 maybe. positioned between the fuel metering device 14 and the fuel metering device cavity 42 within the housing 40. The first and second sealing members,56, 58 may be positioned:on opposing, sides of an air inlet into the.
atomizer 16,. for example, the air intake assembly 24.- The third sealing member 60 may provide-:a fluid-tight seal between the housing 40 and the atomizer .16.

[0063] The atomizer 16 also includes a fuel inlet 44,, an impingement.
surface 46, a plurality of air channels 48, a mixing, chamber 50, and a plurality of secondary outlet orifices .52' in the outlet 54. A face, of the outlet 54 may be perpendicular to a longitudinal axis of the housing 40, or may be arranged at a non-perpendicular angle' relative to the longitudinal axis of the housing 40 to form a conical outlet face that provides a quasi-perpendicular exit face to the:
secondary orifices 52. The fuel inlet. 44 may be positioned in: alignment with the:.
outlet 32 of=
the fuel metering device 14. The fuel inlet 44 may define a single inlet orifice or a.
plurality of inlet orifices through which the supply of fuel provided by the fuel metering device 14 passes to create droplet break up. as. the pressurized flow of fuel moves into the atomizer 16.

10064] The impingement surface 46 may be arranged in alignment with'the outlet 32 of the fuel metering, device 14 and.the fuel inlet 44 of the atomizer 1'6: In some. arrangements, the impingement surface 46.is arranged coaxially with the outlet 32. The impingement surface 46 may have a generally conical shape, which may further be diminished to represent a flat (i.e., planar) surface. In at least one example, the impingement surface 46 includes a portion that is arranged at an angle 74 (see FIG. :19) relative "to a longitudinal axis 72: of the atomizer. 16.
Typically the angle 74 is in 'therange of::abo:ut 0' degrees to about 60 degrees;
add.more.preferably in the range of about.0 degrees' to about 30 degrees. Typically," the smaller the angle 74,. the greater amount. of impact force exerted when the droplets contact the.
impingement, surface 46 to cause breakup of the dro.p.lets; Some of the droplets that contact the..impingenient surface 46 rebound off of the impingement surface :46 into the mixing chamber .50,. The greater the angle 74;. the greater the likelihood of deflection of"the droplets from the impingement surface 46 .with less chance of break up of the droplet occurring.

100651 The impingement surface 46, is.. shown having a generally conical shape with linear. surfaces. In other. arrangements; the impingement surface 46 may have a contoured shape. -or include portions that are contoured. In some arrangements, the impingement. surface 46 'may be slightly concave or recessed.

[00661 The: impingement surface: may include at. least one. surface feature such as. a plurality of protrusions, grooves, divots, or other .type of irregularity.
Providing 'a surface feature may enhance break up of fuel droplets when contacting the impingement surface 46. -The, impingement -surface. may be.. surface treated or constructed of differing material in support of limiting any surface contour change from the resulting ',continual impingement.

[0067] The impingement surface 46 may include an -extended or. enhanced edge 76 hav"ing. overhanging, serrated or other features. Fuel droplets` or portions of fuel droplets that contact the impingement surface 46 may move along the impingement surface. 46 to the edge 76 where the droplets are further broken up at the edge 76 as the droplets move into the mixing chamber 50. In some arrangements, a thin film of droplets. of fuel may collect along the impingement surface '46 and move radially. outward to the edge 76 where the droplets are broken.
up. into smaller sized droplets:. The creation of a thin film of fuel may occur coincidentally with break up of droplets upon, impact of the impingement.
surface 46 and rebounding of droplets of various sizes after contacting the.impingement surface 46.

[0.0681 The impingement surface 46 may have any sized, or. shaped construction. Any portion of the impingement surface 46 may any desired orientation relative to,the fuel metering device 14 and longitudinal axis 72 of the atorniz"er 16.

[9069.1 The pressurized air channels 48 of.the atomizer 16 maybe radially spaced apart :around the :impingement. surface 46 to provide' a flow of Air to the mixing chamber 5.0 and: areas surrounding the impingement surface., 46.. The air channels 48. may extend to. an outer periphery of the atomizer 16 where a supply of pressurized air-is provided via, for example, the air intake assembly 24 (see FIG. 6).
The air channels 48 may be arranged at an angle 78 relative to the longitudinal axis 72 (see FIG. 19). The air channels 48 may have a maximum dimension .D, (i.e.
maximum diameter). The amount of air delivered to' the mixing chamber 50 may be determined at least in part by the number of air channels 48 and. the dimension D,.
The angle 78 is typically in the-range of about 3.0 degrees to about 90 degrees, and more preferably in the range of about 30 to about 60 degrees. The dimension D, is typically in the. range of about 0.5 mm to about 5 mm, and more preferably in the range of about.. I mm to about 2 mm.

1007.01 In addition to 'being 'arranged at an 'angle :78 relative to the, longitudinal axi's 72, the air channels 48 may also be arranged at.an angle-relative to~
a tangent at an outer surface of the atomizer 16. That is to say, the air channels 48 may comprise an angle from tangent greater than -0 degrees :and _less than 90 degrees, wherein .90:degrees is_:aligned..radial or'centered. This additional angled relationship of the air channels 48 may provide a compound. angle fro the air channels. 48 and:
may assist in providing -a helical rotation to the exiting air, thereby generating swiiling'or'vortex.effect. within the inidmg chamber. 50. I'he vortex effect near the.
impingement surface may enhance break up, as well as assist in enhancing evacuation of residual particles during fuel purge, whereas the : vortex.
effect in 'the annulus region may enhance uniformity of- two-phase air/fuel mixture distribution.
from, the secondary outlet orifices. An: caample device that implements vortex chambers within a. fuel -mixing' 'chamber is disclosed in U.S. Published Patent.
Application No. 200710169760, which. is, incorporated herein ;in its 'entirety by this reference:.

100711 The.-mixin,g chamber 50 may, be defined at. least in part surrounding the impingement surface 46 radially outward from the *impin, gemen"t:surface 46. The mixing .chamber 50 may also include an area within the atomizer 1.6 defined between the impingement surface 46 and the fuel inlet 44. The mixing chamber. 50 may be e-a continuous chamber and may extend axially away from the impingement surface 46 toward the outlet 54. The mixing chamber 50 may define a flow path :for.a mixture of air and fuel droplets to travel toward the secondary orifices 52. at. the outlet 54..
Typically; the mixing chamber 50 is sized and arranged to provide a space within which a flow of air provided through the air channels 48 may mix with fuel droplets (i. e:, at. least those fuel droplets that have been broken up upon contact with the impingement surface 46) to create an air/fuel mixture.

[0072] The impingement surface 46 may be defined "as a: structure that extends or protrudes into-Ale. mixing. chamber 5Ø Alternatively, the mixing, chamber 50 may be defined as a. space such as a cylindrical. cavity or annulus that is defined around an, impingement surface and the structure that defines, and supports the impingement surface 46. The bottom of the annulus may be. planar or contoured.
to support enhanced fuel purge.

[0073:] The:.secondary, orifices 52 may be positioned at. an outlet 54 of the atomizer .16. The secondary orifices 52 may be positioned radially and circumferentially, spaced apart. The secondary` orifices 52: may each individually have a maximum dimension ll2 (e.g., maximum diameter) and, be arranged at an angle 80 (see FIG. 19). The collective" cross-sectional area defined by the secondary orifices 52 is .typically less than .the. cross-sectional area of the :mixing chamber 50 (e.g.., cross-sectional area at the interface between the mixing 'chamber 50 and the secondary orifices 5.2). Consequently, fluids under pressure located within.
'the mixing chamber 50: tend to` accelerate as they move" into and through the secondary orifices 52. In at least some examples, the two-phase: air/fuel mixture present: in the mixing chamber 50 accelerates: to. high velocity :(e.,g., . sonic) speeds while passing through the secondary orifices-52. This rapid acceleration tends to break up the fuel droplets in the fuel/air mixture to form a plurality of smaller-sized fuel.
droplets.
Contacting the fuel droplets against the entrance into and sidewalls of the smaller sized secondary orifices 52 may physically break up at least some of the.:.droplets: of the air/fuel mixture.

100.741 The dimension. D2 is typically in the range of about 6.2 mm to about 3 mm and more preferably in the range of about 0.5 ..mm to :about 1..5 m.
Typically,.
the angle 50, is in the. range of about 0. degrees. to about. 45 degrees relative to the longitudinal axis 72, and. more'preferably.in the range of about 0 degrees to about 20 degrees. The angled arrangement of the secondary :orifices 52 tends to disperse.thc fuel mixture to "separate the fuel droplets as they exit the outlet ;54. This dispersion of the fuel. droplets, creates additional separation between the droplets that may accelerate vaporization due to- locally steeper vapor concentration gradients available because the vapor clouds surrounding each of the droplets have less interference with each other.

[0075 The outlet 54 of the atomizer 16 may be constructed as a separate piece that is mounted to the housing 40 in a separate step. FIGS'. 2 and 19 illustrate the construction of outlet 54 as a separate piece. In other arrangements, the outlet 54 may be integrally formed with the: housing 40. Typically, the outlet 54 defines at least a portion of the secondary orifices 52. In some arrangements, the outlet when formed as a separate piece from the housing 40, can be exchanged with an outlet having different sized and angled secondary orifices 52. Different sized and angled. secondary orifices 52 may be-more useful for a given fuel being handled by the fuel system 10. The number of secondary orifices 52 is typically in the range of about 2 to about 20, and, more preferably in the range of about 6. to about 12. The number and relative positioning of secondary orifices..52 may provide certain advantages in disbursing the fuel droplets.

.100761 Referring now to FIGS. 9-11., another example fuel. system 100 is shown. The fuel system 100 includes a base 112 that 'is constructed as an intake port to an engine cylinder head. The base 112 includes; an.. atomizer cavity 120, a-dispense cavity 122, and a cylinder 126. A; valve 128 and ignition member 129 are.
exposed ,within the cylinder 126. :Dispensed fuel,frorn an atomizer 16 is delivered from the dispense cavity 1.22 and then into the cylinder 126 where the fuel is ignited by the ignition member after piston compression 129.

100771 Referring now to FIGS. 12715, another example fuel system 200 his shown. Fuel system .200, is constructed as a direct 'injection:'system wherein the base 212, which is constructed as a cylinder head, is mounted to a cylinder 226.
The base 212 includes an atomizer cavity 220 and :a dispense cavity 222. An ignition member 229 is.exposed within the. cylinder 226. 'Fuel dispensed" from the atomizer 16 directly into the cylinder 226 is ignited by the ignition member. 229 after piston compression.

100781 Other types of fuel systems may benefit from the use of a fuel metering device and atomizer as described herein. The fuel systems described herein may be compatible with many different types of fuel such as, for example, gasoline, diesel fuel and liquid propane. The relatively simple construction of the atomizer, which implements basic physics phenomena related to liquid and gas energy, orifices, physical impingement, pressure differentials, vaporization, rapid acceleration, supersonic speeds, and other considerations may promote certain advantages such as, for example, improved vaporization of fuel at lower pressures, higher fuel flow- rates for a given particle size, reduced complexity in design and manufacturing thereby reducing costs, and-less stringent tolerances as compared to., other systems like direct injection fuel injectors.

10079] The use of multiple physical. mechanisms to break 'up fuel into smaller sized. ;droplets in. sequential order may assist in .sequentially breaking: the droplets into smaller sizes to enhance the.rate of evaporization after dispensing from.
the .atomizer. The rate of evaporizatio'n of a fuel droplet :increases exponentially as the diameter of .the droplet decreases. The. rate of diffusion from the droplet to the, liquid vapor interface between. the: liquid core, and vapor surrounding the fuel droplet maybe expressed by the following Equation 1:

4ipr,D,h,,,;d-,,afnr in Equation 11 . 1--Y;quicl,r Yligiud.m Mass fraction of vapor far from thc. surface Yliquid,i Mass fraction of vapor at "the liquid/vapor interface mliquid = Mass transfer rate. of.liqui.d.

Dliqui4 vapor = Mass diffusivity p = density of the liquid r., = radius of droplet n3.1415.93 (00801 Referring now to FIG. 21-29, an example method, of dispcnsing.fuel with a fuel system is shown and described. The fuel system 10 is referenced throughout FIG. 21-29. Other fuel system embodiments such as fuel systems 1:00, 200 may be operated similarly:

10081.1 The method is initiated. by: creating air pressure within the atomizer.
16 by turning ON an air supply "while maintaining the fuel supply OFF, as:
shown in FIG'S. 21 and 22. This step may also be referred to, as pressurizing the atomizer 1.6., After sufficient air pressure.: is ;obtained within the. atomizer :1.6, excess air flow passes through the, secondaryorifices 52 out of the outlet 54. The airflow 90:
may be referenced as a: plurality of arrows_.96.

[00821 In a 'following. operation step, while maintaining the airflow ON, a supply of fuel is turned ON and delivered by the fuel, metering device 14 into the atomizer 16.. The :supply o f fuel is in the form of at, least :one stream of a plurality of fuel droplets or a" string of fuel droplets that are directed toward. the impingement surface, 46 as shown in FIG.. 23. Upon 'contacting the impingement surface, the first fuel droplets 91 'are broken up into smaller second 'droplets 92 as. shown in FIG. 24.

100831 A thin film of second droplets may collect on the. impingement surface 46 as shown in FIG. 25.. Additional fracturing of the first and second droplets. 9;1, 92 may occur as the thin film travels over the edge 76 -of the impingement surface-46. The second droplets 92 mix with the airflow 90 to create a two-part mixture of air and. second droplets within the ;mixing chamber. 50.
The fuel/air mixture. moves under ,pressure towards the secondary orifices 52, wherein rapid acceleration occurs to increase the, speed of the second droplets. The second droplets may reach supersonic speeds. As the second droplets 92 .pass through the secondary orifices 52, the second droplets 92 are broken up into smaller sized third droplets 94 that are dispersed at the outlet 54 as 'shown in FIG. 26. As the third droplets .94 are dispersed, from the 'atomizer 16. the third droplets: may separate from each other. An vaporization rate for the third droplets- may. increase- as :the. third, droplets 94 continue:to reduce in.size.

[0084] Iria further operation step, the fuel is turned OFF while the airflow is maintained ON;.as;shown..in FIG. 27. This-step may be referred to as, a fuel.purge as the, airflow carries any remaining fuel within, the atomizer 16 out.
through the outlet 54.

100851 In a 'further. operation: step, air is evacuated from,the;atomizer 16 by turning OFF the airflow while maintaining the- fuel OFF:as shown in . F'IG.
18.. in- a final operation' step, the airflow and fuel:. are maintained in an OFF state:.
so that the fuel system remains. idle.

[0086] FIG. 30 illustrates the sequencing of turning the airflow and. fuel supply ON and OFF relative to ignition in-the cylinder of an' engine (b.elow-top dead center (BTDC)). Typically, for a manifold or :intake port installation, the air is maintained ON between about 360 degrees and about 180 degrees BTDC while the fuel is maintained. ON. for a timeframe between about 3;60 degrees.and. about degrees BTDC that is less than- how, long.: the airflow is. maintained ON and also within the range of 360 degrees to 180 degrees BTDC when the air. is.
maintained O.N.

[0087] The-preceding description has been presented only- to illustrate and describe certain aspects, embodiments, and examples of the principles claimed below. It is not intended 'to-be exhaustive or to limit the described principles to any precise forum disclosed. Many modifications and variations are possible in light of the_ above disclosure. Such modifications are contemplated; by the inve=nto:r and within the : scope: of the claims. The. scope of the principles, described is defined by the following claims.

Claims

1. A fuel atomizer, comprising:
a housing having a fuel inlet;

at least one primary orifice positioned at the fuel inlet, the at least one primary orifice configured to disperse a stream of fuel into a plurality of fuel droplets;

a fuel impingement surface against which the plurality of fuel droplets contact to break up the plurality of fuel droplets into a plurality of smaller secondary droplets and create a thin film of secondary fuel droplets on the fuel impingement surface;

at least one pressurized air channel configured to deliver an airflow into contact with the secondary droplets;

a plurality of secondary orifices through which the secondary droplets pass to exit the housing, wherein a size of the plurality of secondary droplets is reduced when passing through the plurality of secondary orifices.

2. The fuel atomizer of claim 1, wherein the at least one primary orifice positioned at the inlet is arranged coaxially with the fuel impingement surface.

3. The fuel atomizer of claim 1, wherein the plurality of secondary droplets accelerate to sonic speed when passing through the plurality of secondary orifices.

4. The fuel atomizer of claim 1, wherein the housing is a manifold.

5. The fuel atomizer of claim 1, wherein the housing is a cylinder head.

6. The fuel atomizer of claim 1, wherein the housing is an intake port into a cylinder head.

7. The fuel atomizer of claim 1, wherein the fuel impingement surface is arranged at an angle in the range of 90 degrees to 135 degrees relative to a longitudinal axis of the housing.

8. The fuel atomizer of claim 1, wherein the plurality of secondary orifices are arranged at an angle between about 0 degrees and about 90 degrees relative to a longitudinal axis of the housing.

9. The fuel atomizer of claim 1, further comprising a fuel metering member that defines the primary orifice.

10. A method of atomizing fuel, comprising:

providing an atomizing device comprising at least one primary inlet orifice, an impingement surface, a mixing chamber, and a plurality of secondary orifices;
passing a stream of fuel through the at least one primary inlet orifice to create a plurality of first fuel droplets;

contacting the plurality of first fuel droplets against the impingement surface to break up the plurality of fuel droplets into a plurality of smaller sized second droplets and create a thin film of secondary droplets on the impingement surface;

mixing the plurality of second droplets with an air flow to form a fuel/air mixture;

passing the fuel/air mixture through the plurality of secondary orifices to shear the plurality of second droplets into a plurality of smaller sized third droplets;
dispersing the plurality of third droplets from the atomizing device.

11. The method according to claim 10, wherein providing the atomizing device comprising arranging the at least one primary orifice, the impingement surface, and plurality of secondary orifices coaxially.

12. The method according to claim 10, wherein mixing the plurality of second droplets with an air flow includes delivering a flow of air in a direction that is at least partially radial.

13. The method according to claim 10, wherein the passing the fuel/air mixture through the plurality of secondary orifices includes rapid acceleration of the fuel/air mixture to sonic speeds.

14. The method according to claim 10, wherein the atomizing device further includes a fuel metering device that defines the at least one primary orifice;
and passing a stream of fuel through the at least one primary orifice includes providing a metered flow of fuel to the at least one primary orifice with the fuel metering device.

15. A pre-combustion fuel mixing device, comprising:
a housing;

a valve enclosed by the housing and arranged to deliver a stream of fuel;

a first nozzle member comprising a plurality of first orifices, wherein passage of the stream of fuel through the plurality of first orifices creates a plurality of first fuel droplets;

an impingement surface arranged in a flow path of the plurality of first fuel droplets, wherein contacting the plurality of first fuel droplets against the impingement surface breaks up the plurality of first fuel droplets into a plurality of smaller sized second droplets;

a mixing chamber;

a plurality of angled passages leading into the mixing chamber through which a flow of air is delivered to mix with the plurality of second droplets to create a fuel/air mixture;

a plurality of second orifices through which the fuel air mixture passes, wherein the plurality of second droplets accelerate to sonic speed when passing through the plurality of second orifices to reduce a size of the plurality of second droplets to a plurality of smaller sized third droplets;

a dispersing nozzle that spaces apart the plurality of third droplets to increase an evaporation rate of the plurality of third droplets.

16. The pre-combustion fuel mixing device of claim 15, wherein at least a portion of the impingement surface is arranged at an angle relative to a longitudinal axis of the device.

17. The pre-combustion fuel mixing device of claim 15, wherein the dispersing nozzle is removably mounted to the housing.

18. The pre-combustion fuel mixing device of claim 15, wherein the plurality of angled passages are arranged at an angle relative to a longitudinal axis of the device.

19. The pre-combustion fuel mixing device of claim 15, wherein the plurality of secondary orifices ares are arranged at an angle relative to a longitudinal axis of the device.

20. A method of vaporizing fuel, comprising:

providing a fuel atomizing device that includes a fuel metering device, an impingement surface, and a plurality of outlet orifices;

controlling a pressurized air source to deliver an air flow through the housing and out of the plurality of outlet orifices;

controlling a fuel, supply to deliver a flow of fuel from the fuel metering device onto the impingement surface, the flow of fuel including a plurality of first fuel droplets that break up into smaller sized second fuel droplets upon contacting the impingement surface;

mixing the second fuel droplets with the air flow;

moving the second fuel droplets through the plurality of outlet orifices, the second fuel droplets fracturing into smaller sized third fuel droplets upon exiting the plurality of outlet orifices;

vaporizing the third fuel droplets as the third fuel droplets disperse from the plurality of outlet orifices;

controlling the fuel supply to turn OFF the flow of fuel while maintaining the air flow;

controlling the pressurized air source to turn OFF the air flow.